Access to cellular components such as nucleic acids is imperative to a variety of molecular biology methodologies. Such methodologies include nucleic acid sequencing, direct detection of particular nucleic acid sequences by nucleic acid hybridization and nucleic acid sequence amplification techniques.
Although access to nucleic acids from the cells of some organisms does not involve particularly complex methodologies or harsh treatments, other organisms have cells from which it is particularly difficult to access nucleic acids or other cellular components. Organisms in the latter group include species of the genus Mycobacteria, yeast and fungi. Usually, the difficulty in cellular component access is a result of organism cell walls which are highly resistant to lysis or disruption, and/or the adherence of certain cellular components such as nucleic acids to cellular proteins and other cellular substances such as pieces of cell walls.
Recently, a new method to access nucleic acids has been discovered which is more fully disclosed in a co-pending patent application Ser. No. 08/614,108, filed on Mar. 12, 1996, the disclosure of which is expressly incorporated herein by reference. Briefly this new method to access nucleic acids involves subjecting a sample of disrupted cells to agitation in the presence of particles to separate nucleic acids from other cellular components. This method has been found to be particularly useful to access nucleic acids from the cells of mycobacterial organisms after those cells have been disrupted by the application of heat.
However, the addition of the particles to the sample of cells was found to present certain difficulties. Generally, the particles are scooped from a bulk quantity into the sample, and thus there tend to be inconsistent quantities of particles delivered to the sample. Also, the scooping and attempt to deliver as precise and consistent an amount of particles to the sample adds additional time to the overall process. Furthermore, in the attempt to deliver a precise amount of particles to the sample, the scoop delivering the particles is brought in close proximity to the opening of the sample container, and thus risks contamination of the scoop, and subsequent contamination of the bulk quantity of particles and all further samples to which particles are added. Moreover, occasionally, a particle becomes lodged at the opening of the sample container in such a manner that a proper seal can not be established. This would often result in sample loss, particularly if a heating step is involved in the process.